Focus on relevant journal papers, textbook chapters, and to a lesser extent conference papers. Odds are you will learn more of what you need for your research from these sources than your graduate classes. Textbooks tend to be more polished and vetted, but they usually offer less cutting-edge content. Of course, you may not need cutting-edge content, especially when building up your understanding of the fundamentals. Conference papers are the opposite: they tend to be the latest-and-greatest work in the research area, but typically they are less polished and verified via peer review. Journal papers are the optimal balance: good peer review (for a strong journal), and relatively state-of-the-art.
What are the biggest mistakes made by PhD students? Well, there are too many to try to list in a single article, but there are some general themes. And in fact, they align well with the mistakes described in many classic personal effectiveness guides.
One common question among new and prospective graduate students: “Is identifying a research topic harder than doing the research and then writing papers / your dissertation PhD dissertation?”
The answer to this question very often depends on your source of funding (if any). If you have a research assistant role in grad school, you are mostly likely given a publication-worthy topic(s) on a silver platter. But you may not like the food on that platter as much, at least initially. Kind of like my kid and nearly any vegetable you put in front of him.
One question I hear frequently from folks who are considering grad school: “How do I get research experience for a PhD?”
“Well,” I reply, “it depends on what you mean by “research experience”.” Do you mean “How do I get work experience doing research that I can employ for a PhD program?” Or do you mean “How do I get experience with the standard research steps that are part of a PhD program, like writing papers, presenting those papers at conferences, presenting a research plan to my committee, and defending my dissertation?”